The present invention relates to a method of manufacturing a preform for a multicore fiber and a method of manufacturing a multicore fiber that are suitable when a multicore fiber including a plurality of cores and a clad surrounding outer circumferences of the plurality of cores is manufactured.
As one of methods of manufacturing a multicore fiber, a stack-and-draw method is known. In the stack-and-draw method, a rod-like preform becoming a core (hereinafter, referred to as a core preform) is surrounded by a preform becoming a clad (hereinafter, referred to as a clad preform) and a gap of the core preform and the clad preform is buried, so that a preform for the multicore fiber is manufactured. In addition, the preform for the multicore fiber is drawn, so that the multicore fiber is manufactured.
As a method of manufacturing a multicore fiber using the stack-and-draw method, patent Literature 1 has been suggested.
In JP 2003-201140 A, clad preforms are arranged at center portions of four core preforms and clad preforms are arranged outside the core preforms. In portions where the core preforms contact in the clad preforms of the center portions and the outside clad preforms, a circular arc surface having almost the same curvature at outer circumferential circles of the core preforms is formed. In addition, in external surface portions in the outside clad preforms, a circular arc surface having almost the same curvature at a circle where the four core preforms contact at the same time is formed.
The four core preforms are gathered using the clad preforms of the center portions and the outside clad preforms, so that a preform for a multicore fiber is manufactured. The preform for the multicore fiber is drawn, so that a multicore fiber is manufactured.
Patent Literature 1: JP 2003-201140 A